Back in June, Microsoft announced that Microsoft Teams will add support for 7X7 grid view that will support up to 49 participants. Yesterday, Microsoft announced the general availability of this feature.
The new Large Gallery feature offers a new way for Teams users to view video up to 49 participants at once on a single screen (7×7). In order to take advantage of this new view, users will need to turn on the new multi-window meeting experience.
Source: Microsoft